The present invention pertains to DC to DC switching power converters, and in particular to DC to DC switching power converters fabricated on semiconductor die.
DC to DC switching power converters are commonly used to convert one available DC voltage to another DC voltage, often needed for a particular set of semiconductor dies. Such power converters may use one or more electrically controlled switches, such as N-channel or P-channel MOSFET devices. As electronic devices become faster, smaller and more portable, the need for improved electrical efficiency in DC to DC converters is becoming more important. Improved electrical efficiency of power converters may result in less power consumption, longer battery life and greater efficiency in electronic systems such as microprocessors.
Furthermore, the operating voltage of high speed microprocessors is reduced as process technology scales and device dimensions shrink. This allows semiconductor die to operate at higher frequencies and the number of transistors integrated on a single semiconductor die to increase. Therefore, more power is consumed by semiconductor die from a power supply. The current supply paths carrying current to a semiconductor die through a circuit board must carry proportionally more current as the voltage level decreases. As a result, the parasitic elements of the current path to a semiconductor die become more pronounced. For example, narrower track widths along with increased current increase series resistance and inductance increasing ripple, power loss and voltage drop. Furthermore, increasing current requires a greater number of package pins and circuit pads for a die which reduces interconnect reliability.
N-channel and P-channel MOSFET devices, for example, have a capacitive gate control input and are turned on by charging the gate capacitance to an appropriate voltage and are turned off by discharging the gate capacitance. Driver circuitry may be used to generate the switching signals to turn on and turn off the switching devices. In many switched power converter applications, the driver circuitry may xe2x80x9cover-drivexe2x80x9d the gate control inputs which consumes unnecessary energy charging the gate capacitance reducing the efficiency of the power converter.
Thus there is a general need for an improved on-die power converter and power conversion method. There is also a need for a more efficient power converter and power conversion method that achieves greater efficiency by reducing the amount of energy to charge and discharge the gate capacitance of switching elements that have capacitive gate control inputs. There is also a need for an on-die power converter and power conversion method that reduces the requirements of off-chip voltage regulation modules.